As integrated circuit technology continues to advance, electronic components such as chips of computers are made to provide faster operational speeds and greater functional capabilities. When a chip operates at a high speed in a computer enclosure, its temperature usually increases greatly. It is desirable to dissipate the generated heat quickly, for example, by using a heat sink attached to the chip in the enclosure. This allows the chip and other high-performance electronic components in the enclosure to function within their normal operating temperature ranges. Oftentimes, fasteners are required for mounting the heat sink to the chip.
Chinese Patent No. ZL 98200376.5 discloses a locking device for mounting a heat sink to a chip mounted on a printed circuited board. The heat sink and the printed circuited board commonly define several pairs of aligned holes around the chip. The locking device comprises several fasteners. Each fastener comprises a spring and a plastic pin. The pin comprises a top portion, an end portion and a shank connecting the top portion with the end portion. The end portion is formed in the shape of a cone with an engaging end having a diameter larger than that of the corresponding hole of the printed circuit board. The shank of each pin is surrounded by the corresponding spring. In use, the end portions of the pins are extended through the corresponding holes of the heat sink and the printed circuit board and engaged beneath the printed circuit board. In this way, the heat sink is mounted on the chip. However, in order to manufacture the pins, a mold is required. The cost for building the mold is usually high. On the other hand, the pins made by plastic material are not heat-resistant. Therefore, the shape of the pin is possibly changed in a high temperature condition, and any deformation of the pin results that the heat sink is not capable of firmly contacting the chip, and thereby reducing the heat dissipating efficiency of the heat sink.